The Z4 offers optional Park Distance Control to help warn the driver about vehicles, pedestrians or other obstacles behind or in front of their vehicle. The TT doesn’t offer a front parking aid.
The Z4 has standard BMW Assist, which uses a global positioning satellite (GPS) receiver and a cellular system to remotely unlock your doors if you lock your keys in, help track down your vehicle if it’s stolen or send emergency personnel to the scene if any airbags deploy. The TT doesn’t offer a GPS response system, only a navigation computer with no live response for emergencies, so if you’re involved in an accident and you’re incapacitated help may not come as quickly.
Both the Z4 and the TT have standard driver and passenger frontal airbags, front side-impact airbags, driver and front passenger knee airbags, side-impact head airbags, front seatbelt pretensioners, plastic fuel tanks, four-wheel antilock brakes, traction control and electronic stability systems to prevent skidding.
BMW pays for scheduled maintenance on the Z4 for 4 years and 50,000 miles. BMW will pay for oil changes, tire rotation, lubrication and any other scheduled maintenance. Audi only pays for the first scheduled maintenance visit on the TT.
There are over 33 percent more BMW dealers than there are Audi dealers, which makes it easier should you ever need service under the Z4’s warranty.
The camshafts in the Z4’s engine are driven by a hardened steel chain, with no maintenance needs. The TT’s camshafts are driven by a rubber belt that needs periodic replacement. If the TT’s cam drive belt breaks the engine could be severely damaged when the pistons hit the opened valves.
J.D. Power and Associates rated the Z4 third among compact premium sporty cars in their 2013 Initial Quality Study. The TT isn’t in the top three.
J.D. Power and Associates’ 2013 survey of the owners of three-year-old vehicles provides the long-term dependability statistics that show that BMW vehicles are more reliable than Audi vehicles. J.D. Power ranks BMW 16th in reliability. With 14 more problems per 100 vehicles, Audi is ranked 23rd.
The Z4 has more powerful engines than the TT:
Horsepower |
Torque |
|
Z4 sDrive28i 2.0 turbo 4 cyl. |
240 HP |
260 lbs.-ft. |
Z4 sDrive35i 3.0 turbo 6 cyl. |
300 HP |
300 lbs.-ft. |
Z4 sDrive35is 3.0 turbo 6 cyl. |
335 HP |
332 lbs.-ft. |
TT 2.0T 2.0 turbo 4 cyl. |
211 HP |
258 lbs.-ft. |
TTS 2.0 turbo 4 cyl. |
265 HP |
258 lbs.-ft. |
As tested in Car and Driver the Z4 sDrive35i is faster than the TTS (automatics tested):
Z4 |
TT |
|
Zero to 60 MPH |
4.8 sec |
5.6 sec |
Zero to 100 MPH |
12 sec |
14.5 sec |
Quarter Mile |
13.5 sec |
14.2 sec |
Speed in 1/4 Mile |
106 MPH |
99 MPH |
On the EPA test cycle the Z4 sDrive28i Auto gets better fuel mileage than the TT (22 city/33 hwy vs. 22 city/31 hwy).
Regenerative brakes improve the Z4’s fuel efficiency by converting inertia back into energy instead of wasting it. The TT doesn’t offer a regenerative braking system.
In heavy traffic or at stoplights the Z4 sDrive28i Manual’s engine automatically turns off when the vehicle is stopped, saving fuel and reducing pollution. The engine is automatically restarted when the driver gets ready to move again. (Start/Stop isn’t accounted in present EPA fuel mileage tests.) The TT doesn’t offer an automatic engine start/stop system.
For better stopping power the Z4’s brake rotors are larger than those on the TT:
Z4 sDrive28i |
Z4 sDrive35i |
TT 2.0T |
TTS |
|
Front Rotors |
13 inches |
13.7 inches |
12.3 inches |
13.4 inches |
Rear Rotors |
11.8 inches |
12.8 inches |
11.3 inches |
12.2 inches |
The Z4’s standard front and rear disc brakes are vented to help dissipate heat for shorter stops with less fading. The rear discs standard on the TT 2.0T are solid, not vented.
The Z4 stops shorter than the TT:
Z4 |
TT |
||
60 to 0 MPH |
102 feet |
107 feet |
Motor Trend |
The Z4 sDriver35i/sDrive35is’ optional 255/30R19 rear tires provide better handling because they have a lower 30 series profile (height to width ratio) that provides a stiffer sidewall than the TT’s optional 35 series tires.
Changing a flat tire near traffic can be dangerous and inconvenient. The run-flat tires standard on the Z4 can be driven up to 50 miles without any air pressure, allowing you to drive to a service station for a repair. Run-flat tires cost extra on the TT.
The Z4 has standard front and rear gas-charged shocks for better control over choppy roads. The TT’s suspension doesn’t offer rear gas-charged shocks.
For a smoother ride and more stable handling, the Z4’s wheelbase is 1.1 inches longer than on the TT (98.3 inches vs. 97.2 inches).
The Z4’s front to rear weight distribution is more even (49.4% to 50.6%) than the TT’s (59% to 41%). This gives the Z4 more stable handling and braking.
For better maneuverability, the Z4’s turning circle is .9 feet tighter than the TT’s (35.1 feet vs. 36 feet).
The Z4’s standard power retractable hardtop allows a seamless transition from an open car, to a completely sealed coupe. The TT doesn’t offer a retractable hardtop.
As tested by Car and Driver, the interior of the Z4 sDrive35i is quieter than the TTS Roadster:
Z4 |
TT |
|
At idle |
47 dB |
47 dB |
Full-Throttle |
79 dB |
80 dB |
70 MPH Cruising |
69 dB |
72 dB |
The Z4 has a larger trunk with its top up than the TT Roadster (10.9 vs. 8.8 cubic feet).
A low lift-over trunk design makes loading and unloading the Z4 easier. The Z4’s trunk lift-over height is 27.2 inches, while the TT Roadster’s liftover is 31.1 inches.
When two different drivers share the Z4, the memory system makes it convenient for both. Each setting activates different, customized memories for the driver’s seat position, outside mirror angle and climate settings. The TT doesn’t offer a memory system.
If the windows are left down on the Z4 the driver can raise them all using the key in the outside lock cylinder or the keyless remote; on a hot day the driver can lower the windows. The driver of the TT can’t use the remote to operate the windows.
In case of a sudden change of weather, the Z4 has a standard remote convertible top which can be raised from a distance to protect the interior of the vehicle from damage. The TT doesn’t offer a remote top, so the driver will have to run to the car, get in, turn the ignition on and raise the top to prevent the interior from being damaged.
Comfort Access standard on the Z4 allows you to unlock the driver’s door, trunk and start the engine all without removing a key from pocket or purse. This eliminates searching for keys before loading groceries, getting in the vehicle in bad weather or making a hurried start to your trip. The Audi TT doesn’t offer an advanced key system.
While driving with high beams on, sensitive light sensors available for the Z4 detect other vehicles which could be blinded and automatically switch to low beams. The TT doesn’t offer automatic dimming high beams.
When the Z4 with available tilt-down mirrors is put in reverse, the passenger rearview mirror tilts from its original position. This gives the driver a better view of the curb during parallel parking maneuvers. Shifting out of reverse puts the mirror into its original position. The TT’s mirror doesn’t automatically adjust for backing.
The Z4 has standard automatic dimming rear and side view mirrors which automatically darken quickly when headlights shine on them, keeping following vehicles from blinding or distracting the driver. The TT has an automatic rear view mirror, but its side mirrors don’t dim.
The Z4’s standard dual zone air conditioning allows the driver and front passenger to choose two completely different temperatures so people with different temperature preferences won’t have to compromise. This makes both the driver and front passenger as comfortable as possible. The TT doesn’t offer dual zone air conditioning.
Optional BMW Apps for the Z4 allows the driver and passengers access to select programs on their smartphones, including reading text messages aloud, playing internet radio stations, tagging songs to buy them later, following twitter accounts and other connected activities without taking their eyes off the road or their hands from the wheel. The TT doesn’t offer factory integrated smartphone program access.
Insurance will cost less for the Z4 owner. The Complete Car Cost Guide estimates that insurance for the Z4 will cost $440 to $1690 less than the TT over a five-year period.
Car and Driver performed a comparison test in its July 2009 issue and they ranked the BMW Z4 sDrive35i higher than the Audi TTS Roadster.
J.D. Power and Associates rated the Z4 second among compact premium sporty cars in owner reported satisfaction. This includes how well the vehicle performs and satisfies its owner’s expectations. The TT isn’t in the top three.
Strategic Vision rates overall owner satisfaction with vehicle quality. With a Total Quality Index of 938, Strategic Vision rated the BMW Z4 24 points higher than the Audi TT for 2012. The Z4 is ranked first in its class and received the 2012 “Total Quality Award.”
The Z4 was chosen as one of Automobile Magazine’s “All Stars” in 2010. The TT has never been an “All Star.”
The BMW Z4 outsold the Audi TT by 33% during the 2013 model year.
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